//
// Created by YANHAI on 2019/5/20.
//

#include <stdio.h>

#define BIG 1

int main()
{
    char str[20] = "C Language", C;
    int i = 0;
    while ((C = str[i++]) != '\0') {
#if  BIG
        if (C >= 'a' && C <= 'z')
            C = C - 32;
#else
        if (C >= 'A' && C <= 'Z')
            C = C + 32;
#endif
        printf("%c", C);
    }
    return 0;
}